In fact, the RBD region of the S protein in SARS-CoV-2 only shares around 74–77% amino acid identity with those of human, civet and bat SARSr-CoVs that were previously reported before the COVID-19 outbreak, although these SARSr-CoVs can all utilize human ACE2 despite their different binding affinities [143,148,149,150,151,152]. This evidence concerns the gene PROS1 and COVID-19.